ES2359934T3 - RETROR REFLECTION SHEET WITH PRINTED IMAGES. - Google Patents

Abstract

A retroreflective sheet that incorporates a stereoscopic image for the prevention of unauthorized manipulations, the retroreflective sheet comprising: - a network sheet of optical elements in which a considerable number of optical elements that transmit light are regularly arranged in at least one fixed location, the network of optical elements being a lenticular lens sheet - a built-in retroreflective printed image sheet that supports a printed image (2), the printed image comprising at least one type of latent image, the latent image being incorporated on the retroreflective sheet a motif that is printed in half ink on a plate that is made by means of an image resolution that is intended to be used for the formation of the stereoscopic image with a number of lines that is the same as the step of contact lens of the lenticular lens, in which the variable image varies depending on The relative position of the network sheet of optical elements with respect to the retroreflective sheet is formed when the printed image is seen through the network sheet of optical elements, the image being stereoscopic variable.

Description

Technical field

The present invention relates to the prevention of unauthorized manipulation of signs, license plates and the like in which a retroreflective sheet is used, making a virtual image of the reflective sheet visible using visual illusion and making use of the virtual image .

Specifically, the invention relates to a retroreflective sheet characterized by comprising at least one printed image - the incorporated retroreflective sheet and a network sheet of optical elements in which a large number of light transmitting optical elements are regularly arranged at less in a fixed location so that, when the printed image is observed through the network sheet of optical elements, a variable image is formed, which varies according to the relative position of the network sheet of optical elements of the retroreflective sheet; or to a retroreflective sheet in which the network sheet of optical elements is laminated on the retroreflective sheet to produce a variable image, which varies according to the relative position of the network sheet of optical elements on the retroreflective sheet.

More specifically, the invention relates to a retroreflective sheet that incorporates a printed image, a sheet that is characterized in that the printed image comprises at least one type of latent image and a lenticular lens sheet is used as the network sheet of optical elements, the latent image incorporated in the retroreflective sheet being a motif printed in half ink on the base of a plate which is elaborated by means of the resolution of the image that must be used for the formation of a stereoscopic image in the same step as the step of Lenticular contact lens.

Likewise, as another embodiment, the invention relates to a retroreflective sheet with built-in printed image which uses a convex lens net sheet as the network sheet of the optical elements and in which the motif incorporated therein it is arranged by means of a half-ink print, the number of lines (c) in the part printed in half-ink and the number of lines (d) of the convex lens net sheet having the ratio defined by:

c = B xd

in which B is a positive numerical value within the range of 0.5 to 1.5.

Background Technique

JP 2004-329355A from Sugiyama, et al. (Patent Reference 1) discloses a stereocropic puzzle printed in variable images which is characterized in that the pieces of the puzzle are composed of a lenticular lens 0.2 to 3.0 mm thick with a lens pitch of 7.9 to 59.1 lines / cm and the microspheres are arranged on a surface of a cardboard envelope on which a motif is formed whose image is resolved in the same step as the lens passage of said lenticular lens, to configure the sterescopic variable image ; and a procedure for manufacturing it.

JP 2004-329355A (Patent Reference 1) also discloses a stereocopic puzzle of variable printing in which each piece of the puzzle consists of a sheet of contact lenses, and the pieces are arranged on a surface of a shell of cardboard in which a motif is formed comprising a portion printed in half ink to configure a stereoscopic, variable image, characterized in that the number of lines (m) of the portion printed in half ink and the number of lines (n) of The dotted lens sheet satisfy the following relationship:

n = 50–150, m = (1/2) - 3/2) xn, m ≠ n,

and a manufacturing process thereof.

However, this patent reference 1 lacks a disclosure regarding the provision of a stereoscopic image on a retroreflective sheet which retroreflects the light. The patent reference 2 puzzle is said to have a great visual effect and great design quality, providing a feeling of fullness and satisfaction of having completed the puzzle, and an increased entertainment capacity. The Reference also states that the puzzle pieces once combined show a great decorative effect. However, the use of its virtual image for the prevention of unauthorized manipulation is not disclosed.

JP Hei 10 (1998) -035083A (Patent Reference 2) discloses a decorative article with dotted motifs that uses a moiré effect, which is manufactured by printing on a surface of a semi-spherical or circular transparent substrate focusing elements constituted by flat-convex contact lenses arched regularly with a constant fine pitch; likewise, the printing on the back of elements of the image of the transparent substrate in the same way, which are arranged in the same way, with those of the focusing elements constituted by flat convex lenses, or elements of the image in a different way. which, however, are arranged in the same manner, with the condensation elements constituted by flat convex lenses, at their angles of intersection offset from those of the condensation elements constituted by flat convex lenses on the front surface; or the printing on a different substrate of colored elements of the permanent substrate of identical or different shape in relation to that of the focusing elements constituted by flat convex lenses, which are arranged identically with the focusing elements constituted by contact lenses planoconvexas, and adhering the substrates to the transparent substrate displacing its crossing angle.

Patent Reference 2, however, does not contain any disclosure regarding the mounting of stereocopic images on a retroreflective sheet which retroreflects the light. Although said Reference states that the decoration of Patent Reference 2 is interesting to see and that, therefore, it can be used to represent plates or printed matter, it does not give information on the use of virtual images to prevent unauthorized manipulation.

Traditionally, the retro-reflective sheet which reflects the incident light towards the light source is well known. The retroreflective sheet has been widely used in the fields of implementation of its retroreflectivity, such as signs that include road signs and construction signals; vehicle license plates, such as cars or motorcycles; safety items, such as clothing and lifeguards; markings on signage plates; Various types of certification stickers

or of reflective plates and the like. In particular, the adoption of retroreflective sheets for various types of license plates or certification stickers is increasing in these years.

As such, the reflective, corner-shaped cube of total internal reflection type, the retroreflective mirror-shaped cube corner sheet, the encapsulated lens-type retroreflective sheet, the enclosed lens-type retroreflective sheet are well known. the retroreflective blade type contact lens open.

A total internal reflection type cube corner retroreflective sheet is described, for example, in US Patent 3,417,959 to Schulz (Patent Reference 3), Mimura JP 2001-026452A (Patent Reference 4, corresponding to the Patent U.S. No. 6,318,866).

A mirrored reflection type cube corner retroreflective sheet is described, for example, in Roland Public Notice JP JP 8 (1996) -510415A (Patent Reference 5, corresponding to US Patent No. 5,376,431 and WO 01/057560 of Mimura, et al. (Patent Reference 6, corresponding to US Patent No. 6,817,724).

Examples of encapsulated contact lens retroreflective sheets include those described in McKenzie JP Sho 40 (1965) -007870B (Patent Reference 7, corresponding to U.S. Patent No. 3,190,178), JP Sho 52 (1977) -110592A McGrath (Patent Reference 8, corresponding to US Patent No. 4,025,159 and JP Sho 62 (1987) -121043A of Bailey, et al. (Patent Reference 9 corresponding to US Patent No. 5,064,272).

Examples of retroreflective lenses of the enclosed lens type are described in JP Sho 59 (1984) 071848A of Belisle (Patent Reference 10, corresponding to US Patent Nos. 4,721,694 and 4,725,494).

US 5,880,885 discloses a retroreflective article showing high retroreflective brightness at large entry angles and low entry angles, and under wet conditions. The article comprises a retroreflective base sheet within a network of retroreflective light elements located on its upper surface, and is indicated for use as a marking on the pavement.

US Patent 2,951,419 discloses an improved deflecting display device which appears to an observer emitting flashes, the device comprising projections or formations as a lens, which are cylindrical in shape and specific areas within which the light will be total or partially absorbed or disseminated.

US 4,676,613 discloses an apparatus for reproducing and capturing images in motion in 3 dimensions that employs a semi-spectral screen which vertically disseminates the light and either horizontally retroreflects or reflects the projected light in a flat mirror.

EP 0 819 953 A2 discloses transparent decorative articles formed from a transparent substrate, glass microspheres, a binder layer and other optional layers, which offer an etching appearance or a rainbow-like appearance depending on lighting conditions and viewing angle. Transparent microspheres can be coated with ink.

These patents on retroreflective sheets, however, do not contain any description related to the incorporation of an image printed on the retroreflective sheet or regarding the use of the stereoscopic image thus obtained for the prevention of unauthorized manipulations.

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[Patent Reference 1] JP 2004.-329355A

[Patent Reference 2] JP Hei 10 (1998) -035083A

[Patent Reference 3] US Patent No. 3,417,959

[Patent Reference 4] JP 2001-026452A

[Patent Reference 5] Public Announcement of JP Hei 8 (1996) -510415A

[Patent Reference 6] WO 01/057560

[Patent Reference 7] JP Sho 40 (1965) -007870B

[Patent Reference 8] JP Sho 52 (1977) -110592A

[Patent Reference 9] JP Sho 62 (1987) -121043A

[Patent Reference 10] JP Sho 59 (1984) -071848A

Disclosure of the invention

We have been seriously engaged in the investigation for the incorporation of a retroreflective sheet, which retroreflects the light, the stereoscopic image and uses the stereoscopic image for the prevention of unauthorized manipulation.

As a result of our studies and advances, we have discovered that a stereoscopic image could be incorporated into a retroreflective sheet by joining a network sheet of light transmitting optical elements with a retroreflective sheet, in which a latent image constituted by a specific printing in half ink that will adapt to the network sheet of optical elements. Our further investigation completed the present invention.

Accordingly, therefore, the invention provides a retroreflective sheet with built-in printed image which is characterized in that a lenticular lens sheet is used as a network sheet of optical elements and because the latent image incorporated in the retroreflective sheet is a motive. printed on the basis of a plate made by resolving the original image for the original stereoscopic image in the same number of lines as the lens passage for the lenticular lens.

According to the invention, a variable image is formed that varies depending on the position of the network sheet of optical elements with respect to the retroreflective sheet when the printed image is observed through the network sheet of optical elements. The variable image is stereoscopic. The network sheet of optical elements is a lenticular lens sheet. The printed image comprises at least one type of the latent image. The latent image incorporated in the retroreflective sheet is a motif that is a half-printed ink based on a plate that is made by means of an image resolution of an image that will be used for the formation of the stereoscopic image with the same step as the step of the lens (a) of the lenticular lens.

According to one embodiment, the contact lens passage (a) and the number of lines (b) the half-ink printing that forms the latent image have the relationship defined by the following equation (1):

b = A x a ……………………………… .. (1)

in which A is a positive value within a range of 1 to 7.5.

According to another embodiment, the network sheet of optical elements is a network sheet of convex lenses. The network motif of the convex contact lens net and the network motif of half-ink printing can be orthogonal networks. The number of lines (d) of the convex contact network can be from 10 to 150.

In accordance with an embodiment of the present invention, a retroreflective sheet with built-in printed image is also provided, which is characterized in that a convex contact lens network sheet is used as the optical element network sheet and in which the latent image incorporated in the retroreflective sheet is formed by a half-ink print, the number of lines (c) of the part printed in half ink having the number of lines (d) of the convex contact lens network sheet the ratio defined by

c = B x d …………………………………… (2)

in which B is a positive numerical value within the range of 0.5 to 1.5. c and d in equation (2) may not be the same. The crossover angle (Ө) of the network motif of the convex contact lens net and the network motif of half-ink printing is 0º <Ө <45º. In another embodiment, c and d in equation (2) can be the same.

When the built-in retroreflective printed image sheet is in the normal state, that is, when the network sheet of optical elements is not laminated thereon, the latent image is visible as an ordinary print and, therefore, it is difficult to manipulate the image latent. Consequently, unauthorized manipulation of the retroreflective sheet incorporating said latent image or unauthorized manipulation of, for example, vehicle license plates or certification stickers using said retroreflective sheet is difficult.

In this way, the effect of preventing unauthorized manipulation can be achieved.

Brief explanation of the drawing

Fig. 1 is a cross-sectional view of a triangular pyramidal cube corner retroreflective sheet

encapsulated Fig. 2 is a cross-sectional view of a triangular pyramidal cube corner retroreflective sheet of type of specular reflection.

Fig. 3 is a cross-sectional view of an encapsulated lens retroreflective sheet. Fig. 4 is a cross-sectional view of an enclosed lens type retroreflective sheet.

List of code numbers

one.

surface protective layer

2.

printed layer

3.

retention layer

Four.

retroreflective element layer

5.

retention layer + retroreflective element layer once integrated

6.

air layer

7.

binder layer

8.

support layer

9.

adhesive layer

10.

removable material layer

eleven.

specular retroreflective layer

twenty-one.

surface protective layer

22

printed layer

2. 3.

retroreflective elements

24.

binder layer

25.

joining parts

26.

support layer

27.

specular reflective layer

28.

air layer

31.

surface protective layer

32

printed layer

33.

transparent microspheres

3. 4.

binding layer of the microspheres

35

focus point adjustment layer

36.

specular retroreflective layer

40. light direction of entry

Best way to put the invention into practice

As the retroreflective sheet to be used in the present invention, the known ones can be used, that is, the total reflection cube corner retroreflective sheet, the specular reflection type cube corner retroreflective sheet, the retroreflective blade encapsulated lens type, the enclosed lens retroreflective sheet, the open lens type retroreflective sheet and the like.

The total internal reflection type cube corner retroreflective sheet is described, for example, in US Patent 3,417,959 to Schultz (Patent Reference 3) and in JP 2001-026452A from Mimura (Patent Reference 4, corresponding to U.S. Patent No. 6,318,866), and said retroreflective sheets, as described herein may be used in the present invention. As for the details of the sheets, refer to those references.

The mirror reflective cube corner retroreflective sheet is described, for example, in Roland JP Hei 8 (1996) -510415A Public Notice (Patent Reference 5, corresponding to US Patent No. 5,376,431) and in WO 011057560 from Mimura, et al. (Patent Reference 6, corresponding to US Patent 6,817,724), and said retroreflective sheets, as described herein may be used in the present invention. As for the details of the sheets, refer to those references.

The encapsulated lens retroreflective sheet is described, for example, in McKenzie JP Sho 40 (1965) 007870B (Patent Reference 7, corresponding to US Patent 3,190,178), in JP Sho 52 (1977) -110592A McGrath (Patent Reference 8, corresponding to US Patent 4,025,159), and in JP Sho 62 (1987) -121043A of Bailey, et al. (Patent Reference 9, corresponding to US Patent 5,064,272), and said retroreflective sheet, as described herein, may be suitably used in the present invention. As for the details of those sheets, refer to those references.

The retroreflective sheet of the enclosed lens type is described, for example, in JP Sho 59 (1984) 071848A of Belisle (reference of Patent 10, corresponding to US Patents 4,721,694 and 4,725,494, and said 8 retroreflective sheets, as is described herein, may be used suitably in the present invention For the details of the sheets, refer to the references cited.

The lenticular lens to be used in the present invention is not particularly limited by its manufacturing process, insofar as it has a thickness ranging from 0.2 to 3.0 mm and a lens pitch of 7.9 to 59.1 lines / cm. It can be prepared by stamping or printing.

When the lenticular lens is manufactured by printing, for example drawing, it is satisfactory that the product has a thickness that makes it possible to make changes in the relative positional relationship between its surface projections and the printed image arranged on the retroreflective sheet. The preferred thickness ranges from 0.2 to 3.0 mm.

As for the material for the manufacture of the lens, it can be any that is a transmitter of light and transparent, for example, a sheet of synthetic resin of general purpose, such as for example polyethylene, polypropylene, polyester, nylon urethane, polyvinyl chloride and acryl. With respect to weathering, the acrylic sheet is preferred, and in consideration of folding, soft vinyl chloride sheet is preferred.

The lenticular lens sheet suitably used in the present invention can be obtained by stamping, such as by means of a synthetic resin sheet, such as stamping rollers.

When the lenticular lens sheet is prepared by printing, preferably a non-uniform pattern is regularly configured by screen printing at a step of 7.9 to 59.1 lines / cm, each of the depressions having a portion of width level from 1 to 50 µm.

As a transparent sheet material that should be used on that occasion, polyvinyl chloride sheet, polycarbonate, polyester, acrylic resin, polystyrene, polypropylene, polyethylene, ABS resin, bioavailable resin, and Similar; transparent or semi-transparent synthetic paper.

A regularly uneven motif is arranged to form a layer of lenticular lenses on the surface of said transparent sheet material as indicated above. Although the convex portions are ordinary convex circular arcs, the defined portions are shaped so that each has a portion at the base of a level of 1 to 50 µm in width. The formation of said leveled portions makes the motif a deep cutting motif and dramatically reduces shear, turbidity, fogging and similar circumstances, achieving an excellent decorative effect.

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The ink to be used for screen printing is not essential, provided it is highly transparent and can form an uneven motif without other operations such as printing. For example, braille ink or the like may be suitably used. As commercially available product, the UV POT -50209 Braille Clear manufactured by Teikoku Ink Co. Ltd.

Soft software programs are available in the market to solve the original of the stereoscopic images with the same number of lines with respect to the lens passage of the lenticular lens blade, which can be used for making clichés. Printing at the point density of 59.1 to 275.6 lines / cm is preferred, which can be carried out by direct printing, for example, offset, oily, UV, screen printing, photogravure printing, flexographic printing and similar by such means as printing on demand; or by transferring the original from the advanced printed transfer paper, using any of the printing procedures mentioned above.

Likewise, it is possible to form partially embossed motifs, by controlling, or by the merit of convex contact lenses of the convex lens net sheet with respect to the half-printed portion, or by controlling half-ink dots in the half-printed portion of the motif, with respect to the convex lens motif of the convex lens net. In particular, it is easier to control the halftone dots that form the motif, with respect to the motif of convex lenses and, therefore, is preferred.

The motif comprising the half-ink printed portion may have a solid monochrome appearance, but when it is formed by combining partially different half-density spots of half-ink and joins with the convex contact lens net, the points to Half ink of partially different sizes can produce a stereoscopic feel.

Proper selection of the coloring relationships between the halftone dots and the background can produce an effect as if a hidden motif were revealed.

Likewise, when a motif is generated by a color process printing of at least two colors and at least one of the colors is incorporated by half-ink printing, for example, when three colors of a five-color processing print are half-printed and the remaining colors, ordinarily printed solid, and the motif is attached to a web sheet of convex contact lenses, the solid printed portion constituting the motifs of two colors appears flat, while the half-printed portion that It constitutes the motif of three colors develops a stereoscopic image that presents a certain depth.

According to the invention, the number (c) in the half-printed portion and the number of lines (d) of the convex contact lens web have the relationship defined by

c = B xd,

B being a positive numerical value within a range of 0.5 to 1.5. When c is not equal to d, a stereoscopic image develops. Outside the exposed range, the stereoscopic image cannot be revealed or is very dark and blurred, without being able to visually provide an interesting image.

According to the invention, even when the c is equal to d, stereoscopic images can still be revealed by joining the arranged motif of the convex contact lens web with the motif of printing in half-ink, at their angles of crossing set at 0º <θ <45º.

According to the invention, stereoscopic images can be obtained when the network sheet of optical elements joins the printed image existing in the retroreflective sheet in any way that the optical elements of the network sheet of optical elements are facing up, or down.

The retroreflective sheet of the present invention is set forth in further detail. As a retroreflective sheet with a built-in printed image of the present invention, any of the systems consisting of the total internal reflection cube corner retroreflective sheets, the specular reflection cube corner retroreflective sheets, the retroreflective reflection cube sheets can be used. encapsulated lens type, closed lens type retroreflective sheets, open lens type retroreflective sheets, and the like.

In the following discussion of certain details of the present invention, firstly a triangular pyramidal cube corner retroreflective sheet, which is a typical embodiment of the total internal reflection type cube corner retroreflective sheet, will be exposed, with Reference to the attached drawings.

FIG. 1 is a cross-sectional view of a triangular pyramidal cube corner retroreflective sheet, in which

(4)

it is a layer of retroreflective elements in which the triangular pyramidal reflective elements are arranged in the tightest compact state,

(3)

it is a reception layer to retain the reflective elements, and

(40)

Indicates the direction of the incoming light. Generally, the layer (4) of reflective elements and the retention layer

(3)

They are integrated (5), but different layers can be laminated. In accordance with the purpose of using the retroreflective sheet of the present invention and the environments in which the sheet is used, a surface protective layer (1), a printed layer (2), a binder layer (7) can be provided to provide a tightly sealed structure to prevent water seepage into the back of the reflective layer (4), a support layer (8), to support the binder layer (7) and an adhesive layer (9) and a removable layer (10) for adhering the anti-reflective sheet to another surface.

The printed layer (2) may normally be disposed between the surface protective layer (1) and the receiving layer (3), or on the surface protective layer (1) or on the reflective plane of the layer (4) of the reflective element. When the surface protective layer is constituted by two or more layers, the printed layer may be interposed between any two layers of the surface protective layer.

The latent image can be formed in the same layer with the printed layer or, in a different layer of the printed layer when the different layers form the printed layer. It is preferred to form it on the front or rear surface of the surface protective layer (the light entry side is designated as the front surface) to obtain a clearer stereoscopic image. From the point of view of security, its arrangement on the rear of the surface protective layer is more preferred.

The printed layer (2) can normally be arranged by means such as gravure printing, screen printing, offset printing, flexo printing, inkjet printing or laser printing.

The material for constituting the layer (4) of the reflective element and the retention layer (3) is not essential, provided that it satisfies the flexibility conditions that is one of the objectives of the present invention although, preferably, it is transparent from the optical and homogeneous point of view.

Examples of materials that may be useful in the layer (4) of the reflective element according to the present invention include the polycarbonate resin, the polyvinyl chloride resin, the methacrylic resin, the epoxy resin, the styrene resin, the polyester resin, fluorinated resin, olefin resin, such as polyethylene resin or polypropylene resin, cellulose resin or urethane resin. To improve weathering, an ultraviolet absorber, an optical stabilizer, an antioxidant and the like, either alone or in combination, can be incorporated. Likewise, various organic pigments, inorganic pigments, fluorescent pigments, dyes, fluorescent dyes and the like can be added as coloring agent.

The same resin used for the layer (4) of the reflective element may be used for the surface protective layer (1), with polyvinyl chloride resin and methacrylic resin being particularly preferred, which stand out in terms of alterability to weathering, solvent resistance and printability.

Also, for the surface protective layer (1), an ultraviolet absorber, an optical stabilizer, an antioxidant and the like can be incorporated, either alone or in combination to improve weathering alterability. Likewise, as a coloring agent, various organic pigments, inorganic pigments, fluorescent pigments, dyes, fluorescent dyes and the like can be added.

Preferably, the surface tension of the surface protective layer (1) is adjusted to at least 32 dynes / cm, to confer favorable printing characteristics, when the surface protective layer should be printed. The printing ink for the surface layer (2) may contain, in addition to a resin component and a coloring agent, various additives, such as a plasticizer, a defoaming agent, a leveling agent, an ultraviolet absorber, a stabilizer optical, a heat stabilizer, a crosslinking agent and the like and, likewise, can be mixed with a solvent to adjust the viscosity.

The resin component that must be used in the ink is not particularly limited, although those with better properties in terms of dispersibility and stability of the coloring agent, solvent solubility, weathering, printability and intimate adhesion to the film, such as melamine resin, epoxy resin, urethane resin or vinyl resin, polyester resin, alkyd resin and the like, which can be used either alone or two or more of them can be combined and copolymerized.

It is a general practice to incorporate an air layer (6) in the rear part of the triangular pyramidal cube corner retroreflective elements, to increase the critical angle in size that satisfies the total internal reflection conditions with respect to the layer (4) of the reflective element. In order to avoid problems such as the reduction of the critical angle due to the infiltration of moisture under the conditions of effective use, preferably, the layer (4) of the reflective element and the support layer (8) are joined together Hermetic form by means of a binder layer (7).

As a means of achieving the seal, those described in US Patents 3,190,178 and 4,025,159, in JP Utility Model Sho 50 (9175) -28669A and the like, can be used.

As the resin intended to be used for the binder layer (7), there may be mentioned methacrylic resin, polyester resin, alkyd resin, epoxy resin and the like, and as agglutination media, the process can be used with favorable results for thermosetting resin agglutination, thermosetting resin agglutination process, ultraviolet curable resin agglutination process, electron hardenable resin agglutination process, and the like.

The binder layer (7) used in the present invention can be applied over the entire surface of the support layer (8), or it can, selectively, be arranged in the portions connecting with the layer (4) of the retroreflective element by means such as printing.

Examples of the material for manufacturing the support layer (8) include the resins useful for manufacturing the layer (4) of the retroreflective element, in general film-forming resins, fibers, fabrics, metallized papers or metal plates such as the stainless steel, aluminum and the like, which can be used either alone or in combination.

The adhesive layer (9) used to glue the retroreflective sheet of the present invention to a metal sheet, a wooden plate, a glass sheet, a plastic sheet or the like, and the removable layer (10) to protect the adhesive layer, they can be selected accordingly from the known materials indicated. As an adhesive, a pressure sensitive adhesive, a heat sensitive adhesive, a crosslinker type adhesive and the like can be used with favorable results. As a pressure sensitive adhesive, a polyacrylic acid ester glue, obtained by copolymerization of the acrylic acid ester, such as butylacrylate, 2-ethylhexylacrylate, isooctylacrylate, non-acrylate, or the like with acrylic acid, can be used , vinyl acetate or the like, silicone resin glue, rubber glue and the like. As a heat sensitive adhesive, acrylic, polyester or epoxy resins can be used.

An example of a mirror reflection cube corner retroreflective sheet, which is another preferred embodiment of the cube corner retroreflective sheet of the present invention, is set forth below, with reference to its cross-sectional view

The same materials described above, with respect to the triangular pyramidal cube corner retroreflective sheet can be used for the surface protective layer (1) the printed layer (2) the retention layer (3), the layer (4) of the reflective element, the integrated layer (5) of (3) and (4), the adhesive layer (9) and the removable layer (10), of the retroreflective corner sheet of triangular pyramidal cube of specular reflection type such and as illustrated in FIG. 2.

Because a metallic specular reflective layer (11) is disposed on the reflective element layer in this embodiment, the printed layer and the latent image are preferably arranged on the front or rear surface of the surface layer , to get a better visibility of the motive.

The latent image can be formed on the same layer with the printed layer or on a different layer when the printed layer is composed of several layers. However, it is preferably formed on the front or rear part (the entrance side of the light is designated as the front part) of the surface protective layer, to obtain a sharper stereoscopic image. From a security point of view, it is even better to form the latent part on the back of the surface protective layer.

The printed layer (2) can be formed by those printing procedures useful with the aforementioned triangular pyramidal retroreflective sheet, by means such as gravure printing, screen printing, offset printing, flexo printing, inkjet printing, and laser printing

For half-ink printing for latent image development, those printing procedures useful in triangular pyramidal retroreflective sheets can be adopted, such as gravure printing, screen printing, offset printing, flexo printing, printing by inkjet and laser printing.

In the case of surface protective printing (1), preferably, the surface printing of the layer is adjusted to be at least 32 dynes / cm, to improve its printing characteristics. The ink of the printing layer (2) may contain various additives other than a resin agent and a coloring agent, such as a plasticizer, a defoamer, a leveling agent, an ultraviolet absorber, an optical stabilizer, a stabilizer of the heat, a crosslinking agent, when necessary. The solvent can be mixed to adjust the viscosity.

The resin component to be used for the ink is not subject to any specific limitation, although melamine resin, epoxy resin, urethane resin, vinyl resin, polyester resin, alkyd resin and similar due to its satisfactory dispersibility and stability of the coloring agent contained therein, its solubility in the solvent, the alterability to the weather, the printability, and the intimate adherability to the film. These resins can be used either alone or as copolymers of two or more of these.

On the surface of the elements of the layer (4) of the retroreflective element of the mirror retroreflective blade corner of the specular reflection type, a metallic specular reflective layer (11) is mounted and, likewise, an adhesive layer (9) It is laminated in direct contact with the specular reflective layer (11). The mirror retroreflective triangle triangular pyramid cube sheet of the present retroreflective invention based on the principle of the specular base and does not require an air layer and therefore does not require a binder layer and a support layer.

In the mirror retroreflective mirror-type cube sheet of the present invention, a specular reflective layer (11) made of metal, such as aluminum, copper, silver, nickel or the like, can be arranged on the surface of the layer (4) of the reflective element, by means such as the deposition of vapors at subatmospheric pressure, chemical coating, ionic bombardment or the like. Of those methods of formation of the specular reflective layer (11), the deposition of vapors at subatmospheric pressure is preferred, because it can lower the temperature of the vapor pressure and, therefore, can minimize the thermal deformation of the retroreflective elements (4) in the vapor deposition stage and fan the color tone of the resulting specular reflective layer (11).

A continuous vapor deposition apparatus intended for the specular reflective layer (11) of aluminum is composed of a vacuum vessel capable of maintaining the degree of vacuum around 931 x 10-4-1197 x 10-4 Pa and, a once a debitter is installed inside to extract an original prismatic sheet composed of two layers of substrate sheet and a protective sheet of laminated surface on the lateral surface of the first light inlet, a reel to rewind the prismatic sheet original vapor deposition, and a heater installed between them that is capable of melting aluminum with an electric heater in a graphite crucible. Pure aluminum pellets with a purity of at least 99.99% by weight are fed into the graphite crucible, and the apparatus can carry out the vapor deposition treatment according to the conditions of, for example, a AC voltage of 350 to 360 V, an electric current of 115 to 120A and a processing speed of 30 to 70 n / min., molten and vaporized aluminum atoms of vapor deposition on the surfaces of the retroreflective elements to obtain a specular reflective layer (11), for example, 800 to 2000Å thick.

FIG. 3 shows an embodiment of an encapsulated lens retroreflective sheet useful for the present invention.

In Fig. 3, a large number of retroreflective elements (23), which are microlens-like reflective elements supplied by thin glass microspheres (23) that partially incorporate a specular reflective layer (27) are arranged in approximately the tighter compact state and a retroreflective element layer is formed by embedding the glass microspheres in the binder layer (24), burying its side of specular reflective layer (27) to be supported by the binder layer. This layer of the retroreflective element contains an air layer (28) that is hermetically sealed in capsules formed by the retroreflective elements (23), the binder layer (24), the surface protective layer (21) and the links (25). which unite these layers as a continuous network.

The encapsulated lens retroreflective sheet can show retro-reflectivity only when it contains a layer of air (28) on the surfaces of the reflective elements (23), as indicated above. The links

(25)

they support the air layer (28) and at the same time prevent the infiltration of, for example, water, on the surface of the retroreflective element layer. When the surface of the retroreflective layer is covered with, for example, water, the light that enters within the retroreflective elements (23) cannot concentrate on the specular reflective layer (27) on the elements due to the change experienced by the refractive index, and retroreflectivity of the leaf is damaged.

The capsules of said encapsulated lens retroreflective sheet, which comprise the retroreflective elements (23) and the retroreflective element layer and the air layer (28) are generically constituted as follows:

(to)

dispersing the glass microspheres on a temporary support sheet that incorporates on its surface a thermoplastic layer, for example of polyethylene, until obtaining the maximum possible uniformity and embedding the lower parts of the microspheres within the thermoplastic layer by heating;

(b)

driving the embedded temporary support sheet of embedded microspheres as obtained in step (a) to a vaporized metal deposition apparatus for the deposition of vapors in a metallic layer [specular reflective layer 27)] on the exposed surfaces of glass microspheres;

(C)

hot pressing on the sheet obtained in accordance with step (b) above, in which the glass microspheres obtained in accordance with step (b) above, in which the glass microspheres that support the specular reflective layer (27) on its exposed surfaces, a thermoplastic resin sheet serving as a binder layer (24), or, when necessary, the thermoplastic resin side of a

laminate consisting of the thermoplastic resin with a support resin sheet to serve as a support layer 26) to bury the specular reflective layer portion (27) of the glass microspheres within the thermoplastic resin layer, and detach the sheet Temporary support to transfer the specular reflective layer

(27)

which supports glass microfibers - on the thermoplastic resin layer,

(d)

lay on the side of the glass microspheres of the sheet obtained in accordance with step (c) above, a resin sheet to serve as a surface protective layer (21), then partially deform the binder layer (24) by means such as thermal stamping from the back side of the binder layer (24) [the opposite of the light inlet side (40)] to heat it with the surface protection layer (21) to form the links (25) ; or

(d ') print a reticular motif to serve as the links (25) with an appropriate resin, on the lateral surface of the glass microspheres of the sheet as obtained in step (c) above, mount on it and adhere to it the surface protective layer (21) to form the links between them.

(e) thus forming the capsules enclosed by the protective surface layer (21), the binder layer (24) and the links (25), which encapsulate the retroreflective element layer and the air layer (28).

The retroreflective sheet may also be provided with a printed layer (s) to transfer information to the observers or color the sheet, a support layer (26) to support and reinforce the binder layer, and a layer of adhesive (9) for gluing the retroreflective sheet on another surface, a removable layer (10) and the like, according to the individual utility and the environment of use of the sheet.

According to this embodiment, the printed layer and the latent image can be incorporated on the front or rear surface of the surface layer or on the binder layer. To improve the visibility of the motif, they are preferably arranged on the front or rear surfaces on the surface layer.

The latent image can be formed on the same layer with the printed layer or on a different layer when the printed layer is composed of several layers. Preferably, however, it is formed on the front or rear part (the entrance side of the light is designated as the front part) of the surface protective layer, to obtain a sharper stereoscopic image. From a security point of view, it is even better to form the latent image on the back of the surface protective layer.

The printed layer (2) can be formed by those printing procedures useful in the exposed triangular pyramid retroreflective sheets, such as gravure printing, screen printing, offset printing, flexo printing, inkjet printing, and printing by laser.

For half-ink printing to reveal the latent image, those useful printing procedures can be adapted with the triangular pyramidal retroreflective sheet, by means such as gravure printing, screen printing, offset printing, flexi printing, jet printing Ink and laser printing.

In the case of printing on the protective surface layer (1), preferably, the surface tension of the layer is adjusted to be at least 32 dynes / cm to improve its printing characteristics. The ink intended for the printed layer (2) may contain various additives other than a resin component and a coloring agent, such as a plasticizer, a defoamer, a leveling agent, an ultraviolet absorber, an optical stabilizer, a stabilizer thermal, a crosslinking agent, and the like, when necessary. A solvent can be mixed to adjust the viscosity.

The resin component to be used for the ink is not subject to any specific limitation, although melamine resin, epoxy resin, urethane resin, vinyl resin, polyester resin, alkyd resin are preferred and the like because of its satisfactory dispersibility and stability of the coloring agent contained therein, the solubility in a solvent, the alterability to the weather, the impermeability and the intimate adhesion to the film. These resins can be presented either alone or as a copolymer of two or more of them.

The glass microspheres (23) used to make the layer of the retroreflective element are made of glass with a particularly high refractive index.

As materials for the composition of each of the layers of this encapsulated lens retroreflective sheet, those materials similar to those described above with respect to each of the corresponding layers of the cube corner retroreflective sheet can be used.

Of these layers, the support layer (26) which is optionally available, when necessary, is generally made of a stronger and more flexible resin than the material used for the binder layer (24) and can be crosslinked by any known means, for example, using isocyanate as the crosslinking agent

or by radiation when necessary.

Likewise, in the retroreflective lens type lens encapsulated with the structure described above, at least one of the layers closest to the entrance side of the light (the side indicated by arrow 40 in FIG.

3) that the hermetically sealed air layer (18), that is, the surface protective layer (1) and / or the printed layer (s) as shown in the FIG. 3, may contain as a mixture within it (s) an ultraviolet absorber and / or an optical stabilizer similar to those cube corner retroreflective sheets, thereby providing an encapsulated lens retroreflective sheet that stands out for its alteration. in the open.

Next, an enclosed lens-type retroreflective sheet which is another preferred embodiment of the present invention with reference to FIG. 4 showing a cross-sectional view of the embodiment.

As shown in FIG. 4, the sheet is composed of a surface layer (31) made of a transparent resin that supports a large number of transparent microspheres (33) that have a high refractive index, such as glass microspheres, as embedded. inside; a layer of transparent microspheres that are embedded in the joining layer (34) of the microspheres to about ½ of their diameters; and a focus adjustment layer (35), which is formed along the curved surface of the layer of transparent microspheres (33) that protrude from the layer (34) of binding microspheres, and whose thickness is manufactured to that is constant so that the specular reflective layer (36) formed thereon is approximately coincident with the optical force of the transparent microspheres (33). Since the transparent microspheres (33) have the high refractive index, the focus adjustment layer (35) and the specular reflective layer (36) are located approximately at the level of the relative positions that optically satisfy the retroreflective light conditions, jointly constituting a retroreflective element of the enclosed lens type.

The printed layer and the latent image in this embodiment can be arranged on this front or rear surface of the surface layer or on the binder layer. Preferably, they are arranged on the front or rear surface of the surface layer, for better visibility of the motif.

The latent image can be formed on the same layer with the printed layer or on a different layer, when the printed layer is composed of several layers. However, preferably, it is formed on the front or rear part (the entrance side of the light is designated as the front part) of the surface protective layer, to obtain a sharper stereoscopic image. From a security point of view, it is still better to form the latent image on the back of the surface protective layer.

The printed layer (2) can be formed by those printing procedures that are useful in the triangular pyramidal retroreflective sheet set forth above, by means such as gravure printing, screen printing, offset printing, flexo printing, jet printing of ink, and laser printing.

For half-ink printing to reveal the latent image, those printing procedures useful in the triangular pyramidal retroreflective sheet can be adopted, by means such as gravure printing, screen printing, offset printing, flexo printing, jet printing Ink and laser printing.

In the case of printing on the protective surface layer (1), preferably, the surface tension of the layer is adjusted to be at least 32 dynes / cm to adjust its printing characteristics. The ink for the printed layer (2) may contain various additives other than a resin component and a coloring agent, such as a plasticizer, a defoamer, a leveling agent, an ultraviolet absorber, an optical stabilizer, a thermal stabilizer . A crosslinking agent and the like, when necessary, a solvent can be mixed to adjust the viscosity.

The resin component to be used for the ink is not subject to any specific limitation, although melanin resin, epoxy resin, urethane resin, vinyl resin, polyester resin, alkyd resin are preferred and the like, for its satisfactory dispersibility and the stability of the coloring agent contained therein, the solubility in a solvent, the alterability to the weather, the printability, and the intimate adherability to the film. These resins can be used either alone or as a copolymer of two or more of them.

The printed image or the latent image may be formed on the front surface (the surface on the entrance side of the light) or the rear surface of the surface protective layer (31) or on the surface of the retroreflective element layer, in a similar way to the retroreflective blade of the cube corner type described above, or to the retroreflective blade of the encapsulated lens type. Also, a similar coloring agent can be used.

As materials for the composition, each of the layers of this enclosed lens-like retroreflective sheet may be useful those materials similar to those described above with respect to each of the corresponding layers of the cube corner retroreflective sheet.

Likewise, in the enclosed lens-type retroreflective sheet, the surface layer and the reflective layer can be mixed with an ultraviolet absorber and / or an optical stabilizer similarly to the cube corner retroreflective sheet described above, thus providing a retroreflective blade of the enclosed lens type that stands out for its weathering alterability.

The retroreflective sheet of the present invention is composed of a retroreflective sheet that supports a printed image and a network sheet of optical elements within which at least a fixed portion is regularly arranged a considerable number of optical elements of light transmitters. The optical element network sheet and the retroreflective sheet are placed separately and the retroreflective sheet can be observed through the optical element network sheet or the optical element network sheet can be laminated on the retroreflective sheet to modify the image by rotation or displacement of the relative position of the first relative to the retroreflective sheet.

The retroreflective sheet according to the present invention has a variable image that changes according to the relative positions of the network sheet of optical elements and the retroreflective sheet. The variable image can be a planar two-dimensional image or a stereoscopic three-dimensional image.

The retroreflective sheet of the present invention can opportunely be used for license plates.

The license plates designated herein are metal plates, such as aluminum, steel or the like, on which the retroreflective sheet is laminated or have a structure on the light inlet side of the retroreflective sheet that It adheres to a sheet of transparent resin with an adhesive.

For example, when it comes to controls, the police officers they inspect can attach a network sheet of optical elements to the license plates under inspection to make stereoscopic images patent.

The retroreflective sheet according to the invention can also be used for certification plates.

For example, inspectors can attach the network sheet of optical elements to certification plates to highlight stereoscopic images.

Examples

[Example 1] Using as a transparent sheet material a polyester film with a thickness of 0.8 mm, a regular uneven motif was printed on the front surface of the film with a pitch of 31.5 lines / cm, each having of the flat portions in the lower parts of the depressions of the motif, a width of 5 µm, by means of silkscreen printing with an ink for embossed letters (braille) (trade name: UV POT -50209 Braille Clear, Teikoku Ink Co. Ltd.). In this way, a lenticular lens 1 was prepared.

On the surface of a triangular pyramidal cube corner retroreflective sheet (trade name: 92802 quality glass Nippon Carbide Industries, Inc.), an original of a stereoscopic image was established in accordance with the step of 31.5 lines / cm. Using the plate manufactured by means of image resolution with a computer program (trade name: Lenticular F / X, Lenticular Development Co.), a half-ink printed image was obtained by UV offset printing.

When the lenticular lens prepared in advance was joined by the printed image formed on the retroreflective sheet, with the front surface of the lenticular lens on the top, a clear stereoscopic image was obtained.

[Example 2] A lenticular lens with a thickness of 0.47 mm with a lens pitch of 28.3 lines / cm was made by stamping, to obtain the lenticular lens 2.

On the surface of the retroreflective sheet used in Example 1, a printed image was formed by means of a print on demand with a density of dots at half ink of 118.1 lines / cm by means of a UV offset printing.

When the lenticular lens 2 was attached on, with its front surface on top, the printed image formed on the retroreflective sheet, a clear stereoscopic image was obtained.

[Example 3] On the surface of an encapsulated lens retroreflective sheet (trade name: F812, ULS quality, Nippon Carbide Industries Inc.) a half-ink printed image was formed by offset printing of 120 to 140 lines.

When a web of convex contact lenses (made of polyester resin, 0.03 mm thick, with 51.2 lines / cm2, manufactured by Meiwa Gravure Co.) joined on the printed image formed on the retroreflective sheet, a clear stereoscopic image was obtained.

[Example 4] Example 3 was repeated except that the convex lens net sheet was attached on the printed image formed by the retroreflective sheet with its back side on top. A clear stereoscopic image was obtained.

[Example 5] A half-ink printed image was obtained in a manner similar to that of Example 3, except that a retroreflective lens type enclosed sheet (trade name: 48012, ELG license plate quality, Nippon Carbide Industries, Inc.) was used as retroreflective sheet.

When a web sheet of convex contact lenses was attached to the printed image formed on the retroreflective sheet, similar to that of Example 3, a clear stereoscopic image was obtained.

[Example 6] A printed image was formed in a manner similar to that of Example 5, except that half-ink printing on the retroreflective sheet was carried out with 51.2 lines / cm.

When a convex lens sheet was superimposed on the printed image formed on the retroreflective sheet in a manner similar to that of Example 3, no stereoscopic image was obtained, but when the convex lens sheet was rotated on the printed image, the stereoscopic image was modified at the rate of rotation, appearing clear at times.

[Example 7] A printed image was formed in a manner similar to that of Example 5, except that the number of lines of half-ink printing was raised to 300.

When the convex lens sheet was attached to the printed image formed on the retroreflective sheet in a manner similar to that of Example 3, a stereoscopic image was obtained, which, however, was not clear.

[Example 8] A polyethylene terephthalate film was used as a carrier film and, on which a mixture of 50 parts of a polyester resin solution manufactured by Mitsui Chemicals Inc. (trade name: ALMATEX HMP-90S) was applied, 10% by weight of a polyester resin solution manufactured by Mitsui Chemicals Inc. (ALMATEX P-110), 40 parts by weight of a polyester resin solution manufactured by Mitui Chemicals Inc. (trade name: ORESTAR Q-203 ), 11 parts by weight of a solution of methylated melamine resin manufactured by Sanwa Chemical Co, (trade name: NIKALAC MS-11), 0.2 parts by weight of an acrylic resin manufactured by Mitsui Chemical Inc. (trade name: RESIMIX RL-4), a part of 0.005 by weight of an anti-blocking agent manufactured by Toshiba Silicone Co. (trade name: TSF 4445), 6 parts by weight of a cellulose derivative manufactured by Tokushu Shikiryo KK (trade name: CAB), 1 part of 0.6 by weight of an ultraviolet absorber manufactured by Ciba Specialty Chemicals, K.K. (trade name: Tinuvin 213), 1 part of 0.1 by weight of a catalyst manufactured by Dainippon Ink & Chemicals, Inc. (BECKAMINE P-198) and 25 parts by weight of a solvent mixture, MIKB / toluene / IPA = 66/32/2 and allowed to dry to obtain a film-1 with a thickness of 32 µm.

Likewise, on film-1 an image was printed in half-ink by offset printing with a transparent blue ink (manufactured by Tokushu Shikiryo K.K., trade name: N-3506) with a line density of 120 to 140.

On the film-1 incorporating the printed image, a mixture of 100 parts by weight of a toluene / MIBK solution (1: 1) (solid content equal to 40%) of MMA / EA / 2HEMA copolymer was hardened. (weight ratio: MMA / EA / HEMA = 21/65/14), 8 parts by weight of an isocyanate crosslinking agent manufactured by Sumitomo Bayer Urethane Co. Ltd. (trade name: SUMIDUR N-75) and 35.8 parts by weight of a mixture of MIBK solvent / toluene / high boiling solvent (from Shinnippon Petrochemicals Co., Ltd. trade name: SUPERSOL 1500) with a ratio of 39/16/45, to obtain a film-2 which offered a thickness combined with the film-1 of 63 µm.

On film-2, glass microspheres manufactured by Union Beads K.K. (trade name: UNIBEADS N34S) were dispersed and then the film-2 was dried and hardened.

Likewise, on the microspheres, a mixture of 100 parts by weight of a solution of toluene / xylene / ethylacetate / n-butanol (11/45/29/15 (solid content = 30) was applied and hardened to form the film-3 %) of the MMA / BA / AA copolymer weight ratio: MMA / BA / AA = 35/50/15), 5.5 parts by weight of a solution of methylated melamine resin manufactured by Sanwa Chemical Co. (trade name: MIKALAC MS-11) and 39.3 parts by weight of a solvent mixture of MIBK / toluene = 2/3.

On film-3, subatmospheric pressure vapor aluminum was deposited to form film-4.

Likewise, as a removable paper, the product of Lintech K.K. (trade name E2AP-LK-BL (P)) on which a mixture of 100 parts by weight of an ethyl acetate / toluene solution (1/1) (solid content = 34%) of BA / AA copolymer was applied and dried (weight ratio: BA / AA = 90/10), one part by weight of an isocyanate crosslinking agent manufactured by Nippon Polyurethane Industries Co. (trade name: CORONATE L) and 17.8 parts by weight of ethyl acetate as solvent, It was applied and dried to form an adhesive layer with a thickness of 40 µm.

After gluing this layer of adhesive with the film-4 previously formed, the carrier film was peeled off to obtain a retroreflective sheet incorporating the printed image inside.

Similarly to Example 3, a convex lens sheet was attached to the image printed on the retroreflective sheet and in this way a clear sterescopic image was obtained.

[Example 9] on the surface of the retroreflective sheet used in Example 5, a printed image was formed by polychromatic offset printing with 120 to 140 lines, in which three colors were printed in half ink and the other two colors were printed in solid mode

When a convex lens sheet was attached to the printed image formed on the retroreflective sheet in a manner similar to that of Example 3, the tricolor half-ink printed part provided a clear stereoscopic image but the solidly printed part did not produce a stereoscopic image.

[Example 10] On the surface of the retroreflective sheet that was used in Example 1, a printed image was formed by offset printing of 120 to 140 lines.

The backside of the convex lens net sheet was glued together with the adhesive layer as prepared in Example 8, the removable paper was peeled off and the exposed surface was adhered to the retroreflective sheet from above the printed image formed in the retroreflective sheet. After which a retroreflective sheet was obtained in which the stereoscopic image was always visible.

[Example 11] The convex lens net sheet used in Example 3 was glued to the retroreflective sheet used in Example 6, such that its angle of crossing occurred at 15 °. In this way, a retroreflective sheet was obtained in which the stereoscopic image was always visible.

[Example 12] The adhesive layer, as prepared in Example 8, was glued to the back of the lenticular lens sheet that was used in Example 1, and the removable paper was peeled off, to adhere the sheet of Lenticular lens to the retroreflective sheet as prepared in Example 8, from above the printed image as formed in the retroreflective sheet. In this way a retroreflective sheet was obtained in which the stereoscopic image was always visible.

[Example 13] A polyester film with a thickness of 0.8 mm was used as a transparent sheet material, and about a half of the front surface area of the polyester film was printed a regular uneven motif with a step of 31 , 5 lines / cm, each of the portions in the interior parts of the depressions of the motif having a width of 5 µm, by means of a silkscreen printing with an ink for the relief letters (trade name: UV POT -50209 Braille Clear, Teikokou Inc. Co. Ltd.), This way a partial lenticular lens-3 was prepared.

When the lenticular lens-3 was attached on, with its front surface on top, the printed image formed on the retroreflective sheet that was prepared in Example 1, the part where the lenses were present, a clear stereoscopic image was obtained, while the part where the lens was absent, the printed image remained as it was.

[Example 15] The lenticular lens-2, as prepared in Example 2, was attached side by side to the polyester film that was used in Example 1, to achieve a lenticular lens-4.

Similar to that of Example 13, the lenticular lens-4 was attached to the image printed on the retroreflective sheet of Example 1. In the part where the lenses were present, a clear stereoscopic image was obtained, while in the part where the lens was absent, the printed image remained as it was.

Industrial applicability

The invention makes a virtual image appear on a retroreflective sheet, using visual illusion. Making use of the virtual image, the invention provides a retroreflective sheet useful for the avoidance of unauthorized manipulations of signs, license plates and the like using the retroreflective sheet.

Claims (16)

1. A retroreflective sheet that incorporates a stereoscopic image for the prevention of unauthorized manipulations, comprising the retroreflective sheet: -a network sheet of optical elements in which a considerable number of optical elements that transmit light are regularly arranged at least in a fixed location, the network sheet of optical elements being a lenticular lens sheet - a built-in printed image retroreflective sheet that supports a printed image (2), the printed image comprising at least one type of latent image, the latent image incorporated in the retroreflective sheet being a motif that is printed in half ink on a plate that it is made by means of an image resolution that is intended to be used for the formation of the stereoscopic image with a number of lines that is the same as the lens passage (a) of the lenticular lens, wherein the variable image that varies depending on the relative position of the network sheet of optical elements with respect to the retroreflective sheet is formed when the printed image is seen through the network sheet of optical elements, the image being variable Stereoscopic

2.

The retroreflective sheet according to claim 1, characterized in that the network sheet of optical elements is laminated on the retroreflective sheet to produce a variable image that varies depending on the relative position of the network sheet of optical elements with respect to the sheet retroreflective

3.

The retroreflective sheet according to claims 1 or 2, characterized in that the lenticular lens is 0.2 to 0.3 mm thick.

Four.

The retroreflective sheet according to claim 3, characterized in that the lens passage (a) of the lenticular lens is 7.9 to 59.1 lines / cm.

5.

The retroreflective sheet according to any of the preceding claims, wherein the step of contact lens (a) and the number of lines (b) of the half-ink printing that forms the latent image have the relationship defined by the following equation ( one):

b = A x a ……………………………… (1) in which A is a positive value within a range of 1 to 7.5.

6.

The retroreflective sheet according to claims 1 or 2, characterized in that the network sheet of optical elements is a convex lens net sheet.

7.

The retroreflective sheet according to claim 6, characterized in that the network motif of the convex contact lens net and the network motif of half-ink printing are orthogonal networks.

8.

The retro-reflective sheet of claims 6 or 7, characterized in that the number of lines (d) of the convex lens network is 10 to 150.

9.

The retroreflective sheet according to any one of claims 6 to 8, wherein the latent image of the retroreflective sheet is formed by a half-ink print (c) of the half-ink print portion of the number of lines (d ) of the convex lens network have the relationship defined by the following equation (2):

c = B x d …………………………………… .. (2) in which B is a positive value within a range of 0.5 to 1.5.

10.

The retroreflective sheet according to claim 9, characterized in that c and d in equation (2) are not equal.

eleven.

The retroreflective sheet according to any one of claims 6 and 8 to 10, characterized in that the crossover angle (θ) of the network motif of the convex contact lens net and the network motif of half-ink printing is of 0º <θ <45º.

12.

The retroreflective sheet according to claims 9 or 11, characterized in that c and d in the equation

(2) are the same.

13.

The retroreflective sheet according to any one of claims 1 to 12, characterized in that the retroreflective sheet is a cube corner sheet of total internal reflection type, and a corner retroreflective cube sheet of specular internal reflection type, a retroreflective sheet encapsulated contact lens type, an enclosed contact lens retroreflective sheet or an open contact lens type retroreflective sheet.

14.

The retroreflective sheet according to any one of claims 1 to 13, characterized in that the printed image is formed by a transparent coloring composition and the latent image portion has retroreflectivity.

fifteen.

A license plate on which the retroreflective sheet with printed image incorporated according to any one of claims 1 to 14 is used.

16.

A certification sticker in which the retroreflective sheet with printed image incorporated in accordance with any one of claims 1 to 14 is used.